He plans to… “Free time” has been in very limited supply this week.
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I know, that is why I put it like that 
. I understand and hope that the rest of your week goes well Travis.
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I will start with this here.
You cannot look at pigmentation in animals with an “artist eye” toward how you would mix paints. This is a tangled mess of protein chemistry, physics, and neurobiology. And probably some other stuff I am forgetting about at the moment
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Melanins across the animal kingdom are brown-based
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This is a great observation and leads directly into what I mentioned above regarding protein chemistry. We will get to this.
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Yes. And also no. 
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I will get to this too 
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Now… To dust off some of the less used parts of my brain…
Nathan’s citation of my previous post is a good place to start. That was the most simplified version of the situation, however. Instead of thinking of just two layers of coloured film, imagine you are looking at twenty (20) layers. While some layers may be a single uniform colour, others may be a gradient from the top to the bottom, others may have colour randomly splotched on it, some may have both colours, some may have no colour at all. Also, some of the layers may have crushed pieces of glass on them, and these can be large fragments or small fragments. And, like the pigmentation, it can be scattered or collected or mixed.
This is a simplified biophysiology of ball skin
Now, think about changing the amount or distribution of pigment or glass on any layer or group of layers and the effect it will have the appearance of the whole when viewed from the top. This is the first facet of protein chemistry and physics we need to think about
A part of the change you will see is due to a change in the concentration of one of the pigments with regards to depth, obviously. But part of the change is also due to how the remaining pigments (plural) change the overall absorption/reflection of light. And also how that altered absorption/reflection then interacts with the glass fragments which changes the diffraction. And also also, how the now “altered” lightwave then stimulates your eye.
Which brings us to another facet of protein chemistry, physics, and neurobiology. So… Fun fact, we do not see the colour yellow. Or brown. Or orange. Or purple. The colour-detecting structures in the human eye are only able to detect three rather narrow wavelengths of light in the red (~560nm), green (~530nm), and blue (~420nm) spectra. When we “see” yellow what is actually happening is that our red and green detectors are being stimulated at roughly equal levels and our brain decides that the colour must be somewhere in the middle. And if something, like say a greater or lesser amount of pigment, alters the wavelength(s) of light hitting our detectors it is going to change the way the brain interprets the signal. This is the main reason why the alien head on a ball can appear as tan (wildtype) or orange (Banan) or yellow (Albino) depending on the amount of melanin present/absent.
Bane also brought up the ontogenetic colour shift we see in balls (and many other species). This is yet another facet of protein chemistry and physics. The first, and simplest, explanation is just a matter of changing concentration – a specific amount of pigment is going to appear more vibrant when it is concentrated in a smaller area than over a larger area. So 1000 pieces of brown pigment are going to appear much darker when crammed into a 1cm x 1cm space compared to when they can spread over a 5cm x 5cm space (for an easy visualization of this, fill a shot glass with coffee and look down on it from directly overhead and it looks really dark. Now take that shot glass and pour it into a large shallow bowl and the exact same amount of coffee looks pale brown.) As a snake grows, the area of the animal increases and therefore the concentration of pigment decreases resulting in an overall paling of the colours on the animal. Second, pigments are dynamic molecules and subject to chemical interactions, specifically oxidation. As time goes by, the pigments are altered/degraded by oxidation and so their tone changes. Third, maturation brings with it other fun things like hormone changes that in turn result in altered expression of genes. Sometimes this leads to changes in the synthesis of both quantities and also types of pigments. The net effect being a potentially dramatic change in the appearance of an animal
Bane also commented on morphs that seem to have a more orange hue to them but lamented that he did not have an easy explanation at hand. This would be the same phenomenon but with xanthins instead of melanin. If you are at all familiar with baking, think about food colouring. Yellow food colouring actually appears as a really deep orange in the tube and it is only when you spread that single “orange” drop out into a kilo of wet powdered sugar that it appears yellow. It is all concentration and chemistry, no red pigment needed.
And all of that is just dealing with pigment levels. Add in the “crushed glass” factor and how that will also impact reflection/refraction/absorption/dispersion and you get an even more dynamic/chaotic system where relatively small perturbations can have large impacts
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Lav is not a T-neg mutation.
The T in T-neg is a shorthand for the protein tyrosinase. There is only one gene for tyrosinase so if you mutate that gene in such a way as to be rendered non-functional then there is no tyrosinase in the animal. But, like the Highlander, there can be only one. It is impossible to have two independent and unrelated mutations that are both T-neg.
Lav is a mutation to the tyrp1 gene if I remember correctly, which encodes an entirely different protein - tyrosinase-related protein-1. Lav animals have a perfectly functional copy of the tyrosinase gene and are therefore, by definition, T-pos
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No it is not.
The prefix “hypo-” is Latin for ‘less than normal’. There are only two pigments in ball pythons: melanin and xanthin. The Banana mutation has no change in the expression of xanthin but a reduced expression of melanin. So the Banana morph, which has “less than normal” expression of melanin is therefore, by definition, hypomelanistic.
This same applies to Lav and to Caramel and to Candy and to Ultramel and to Trojan and…
Just because the majority of the reptile hobby are unintentionally or willfully ignorant on this matter does not change the simple fact
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Not really…
Historically, the term “albino” was assigned to freaks of nature that white with red eyes. The most common occurrence for this was seen in mammals, because those were more commonly encountered by the general masses of humanity. Mammals only have melanin as a pigment so the red-eyed/white phenotype was an acceptable catchall. When rarities like white and yellow or white and orange or white and red non-mammals were encountered, people were often able to make the logical leap of connecting the red-eye phenotype defining these as “albinos” as well.
Then came the genetic and molecular biology era and scientists realized that there were other, less common, genotypes that gave rise to an albino-like phenotype. This then led to the identification of amelanism and the tyr-pos and tyr-neg types of albinism. This also led to a bit of a shift in the informal nomenclature where “albino” was now used to denote the classic phenotype (red-eye/white) that was mostly, but not always, the result of amelanism. This nomenclature divide has persisted and been reinforced over time with modifiers to denote cases where the phenotype was similar but genetically the mutation was not tyr-neg, e.g., Lavender Albino, Purple Albino, Green Albino, etc. The divergence propagated further to situations were the phenotypes that were not even close to albinism but were still obviously melanin-based, e.g., Caramel Albino and the like.
But the historical origin still falls back to the term “albino” now being synonymous with cases that are proven (or reasonably suspected) to be Amelanism with “albinism” or “albinistic” covering the broader range of tyr-pos and tyr-neg mutations
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Thanks for answering this one! That whole entire post was gold! I learned and even understood everything with the way you described it! Very nicely explained! I do have one more question for you though; what do you do in your off time? Rocket scientist? Use quantum physics to develop time travel through the use of wormholes?
I mean you got some knowledge bouncing around in between your ears! Thanks again for all the great info! I believe that should have answered this one as complete as possible!
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Dude makes the finest 
s 
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This is why we love Travis 
. It only helps that he’s such a great guy too.
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What is this “off time” thing of which you speak???
As Thomas notes, I enjoy cooking and baking (I bake something for my coworkers pretty much every week). I also cultivate carnivorous plants, pretty much just Sarracenia at this point but once upon a time I had a collection of over 500 specimens representing pretty much every genus that exhibits carnivority. Obviously, I do herps. Right now that involves a lot of cage build/rebuild as I redesign my snake rooms.
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